ESQL shared variables are often used to cache the contents of database tables in WebSphere Message Broker and IBM Integration Bus. The problem with this approach is that ESQL SELECT operations perform sequential searches, which become progressively slower as the cache grows. This article introduces a new way of structuring the cache that scales well, remaining faster than accessing the database even when exceeding 10,000 rows. The new cache structure is transparent to applications, so you can safely convert existing caches, and significantly reduce response time and CPU usage.